TY - JOUR
T1 - Conference key agreement in a quantum network
AU - Pickston, Alexander
AU - Ho, Joseph
AU - Ulibarrena, Andrés
AU - Grasselli, Federico
AU - Proietti, Massimiliano
AU - Morrison, Christopher L.
AU - Barrow, Peter
AU - Graffitti, Francesco
AU - Fedrizzi, Alessandro
N1 - Funding Information:
This work was supported by the UK Engineering and Physical Sciences Research Council (Grant Nos. EP/T001011/1.). F Graffitti acknowledges studentship funding from EPSRC under Grant No. EP/L015110/1. F Graselli acknowledges support from the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) under Germany’s Excellence Strategy - Cluster of Excellence Matter and Light for Quantum Computing (ML4Q) EXC 2004/1 -390534769.
Publisher Copyright:
© 2023, Springer Nature Limited.
PY - 2023/8/22
Y1 - 2023/8/22
N2 - Quantum conference key agreement (QCKA) allows multiple users to establish a secure key from a shared multi-partite entangled state. In a quantum network, this protocol can be efficiently implemented using a single copy of a N-qubit Greenberger-Horne-Zeilinger (GHZ) state to distil a secure N-user conference key bit, whereas up to N-1 entanglement pairs are consumed in the traditional pair-wise protocol. We demonstrate the advantage provided by GHZ states in a testbed consisting of a photonic six-user quantum network, where four users can distil either a GHZ state or the required number of Bell pairs for QCKA using network routing techniques. In the asymptotic limit, we report a more than two-fold enhancement of the conference key rate when comparing the two protocols. We extrapolate our data set to show that the resource advantage for the GHZ protocol persists when taking into account finite-key effects.
AB - Quantum conference key agreement (QCKA) allows multiple users to establish a secure key from a shared multi-partite entangled state. In a quantum network, this protocol can be efficiently implemented using a single copy of a N-qubit Greenberger-Horne-Zeilinger (GHZ) state to distil a secure N-user conference key bit, whereas up to N-1 entanglement pairs are consumed in the traditional pair-wise protocol. We demonstrate the advantage provided by GHZ states in a testbed consisting of a photonic six-user quantum network, where four users can distil either a GHZ state or the required number of Bell pairs for QCKA using network routing techniques. In the asymptotic limit, we report a more than two-fold enhancement of the conference key rate when comparing the two protocols. We extrapolate our data set to show that the resource advantage for the GHZ protocol persists when taking into account finite-key effects.
UR - http://www.scopus.com/inward/record.url?scp=85168655586&partnerID=8YFLogxK
U2 - 10.1038/s41534-023-00750-4
DO - 10.1038/s41534-023-00750-4
M3 - Article
AN - SCOPUS:85168655586
SN - 2056-6387
VL - 9
JO - npj Quantum Information
JF - npj Quantum Information
M1 - 82
ER -